<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title>Document</title>
</head>
<body></body>
<script>
   var r = 80;
   var pai = 3.14;
   var c = 2 * pai * r;
   var s=pai*r*r;
   console.log("半径" + r + "的圆周长是：" + c);
   console.log(s);
</script>
</html>
